Aphids are important insects because they are a major food resource in ecosystems and are among the main crop pests in temperate regions. That is why researchers at the Joint Research Unit on the Biology of Organisms and Populations Applied to Plant Protection at the INRA Rennes Center working with the EXAMINE Consortium, Rothamsted Research, the Institut Français de la Biodiversité (French Institute for Biodiversity), Agroclim, and Météo France (the French Weather Bureau) are studying the impact of global warming on aphid populations. The study involves processing the data from the European EXAMINE network (est. 1968) to which INRA researchers belong.
For the study, the researchers selected eight of the European network's trapping sites in Western Europe, including four sites in France (Rennes, Colmar, Arras, and Montpellier), 3 English sites and 1 Scottish site. The trapping sites are typical of contrasting biological and geographical situations and have been operating for 28 to 38 years. The research has shown that the number of aphid species has substantially increased over the past 40 years, i.e., an average of one species per year and per site. The other major impact of warming, which was observed for the study, is the longer period of aphid activity, which is about one year per year on average. For instance at the English Rothamsted site, the first spring aphid migrations occurred around May 24 in the sixties, and now happen around May 7. At virtually all the EXAMINE sites, advancement of the first migration varied, depending on the species and sites, from one day every five years to more than three days per year, or from one to ten weeks over the past forty years.
